1. Field of the Invention
This invention relates to a method and apparatus for the detecting of objects, and more particularly to a method and apparatus which detects objects and provides a detecting signal in response thereto, while minimizing the generation of such a detection signal in response to various objects which may proximately reside near the detector apparatus.
2. Discussion
Object detection systems are used in a wide variety of applications, including that associated with collision avoidance. In collision avoidance systems, these object detectors are usually mounted upon the body of a moving vehicle and are made to generate a beam of radiation such that the generated beam is caused to strike a close object and be reflected back to the object detector. The receipt of this reflected beam of generated radiation then usually causes the object detector to produce an amplified signal to the operator of the vehicle warning the operator that an object is close by. These object detectors have usually defined a modifiable threshold detection distance which defined the distance an object had to be from the detector in order to be detected. This threshold distance was modifiable up to an upper limit defined by the constraints associated with the elements of the detector.
While these object detector systems have proven to be invaluable in the operation of motorized vehicles, there have been a substantial number of drawbacks associated therewith. Perhaps the largest drawback associated with these object detectors, as used within collision avoidance systems, is that these object detectors have been seen to issue many false warnings to the operators of these motor vehicles causing undue alarm and improperly interfering with the operator's attention, thereby increasing the possibility of accidents due to abrupt stops or diverted attention. These false detecting signals have usually been the result of the reflection of the generated beam by suspended particulates (i.e., snow, fog, rain, or other forms of atmospheric precipitation) which usually lies in close proximity to the object detector between the object detector and the object to be detected, and which causes a reflection of a generated beam back to the detector and causing a false indication of the closeness of the object thereto.
A closely related drawback associated with the object detectors as used in collision avoidance systems is that the ability to detect a closely positioned object is highly determinative of the amount of radiation which is reflected back to the object detector. That is, it has been found that these object detectors have had a great deal of difficulty in detecting very dark objects, since these dark objects absorb much of the radiated energy which is generated from the object detectors and which causes only a very small amount of this energy to be reflected back thereto. This drawback has been overcome, in many instances, by the use of increased amplification or gain (i.e. referred to as "Excess Gain") by the detector. This Excess Gain increases the amplitude of the signal produced by the detector in response to the received reflected beam of radiation.
While this Excess Gain has increased the ability of the object detector to detect very dark objects, it has further amplified the problem associated with the generation of false detection signals by the particulate material which is present in close proximity to the object. That is, this Excess Gain decreases the threshold amount of sensitivity needed by the detector in order for the detector to generate a detection signal, thereby increasing the probability of a false detection signal. The present invention is then directed to overcome substantially all of the deficiencies as stated above.